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TY - CONF AU - Ding, L.H. AU - Liang, J. AU - Liu, H. AU - Xie, Z.P. ED - Schaa, Volker RW TI - Active Magnetic Field Compensation System for SRF Cavities J2 - Proc. of IBIC2018, Shanghai, China, 9-13 September 2018 C1 - Shanghai, China T2 - International Beam Instrumentation Conference T3 - 7 LA - english AB - Abstract: Superconducting Radio Frequency (SRF) cavities are becoming popular in modern particle accelerators. When the SRF cavity is transitioning from the non-conducting to the Superconducting state at the critical temperature (Tc), the ambient magnetic field can be trapped. This trapped flux may lead to an increase in the surface resistance of the cavity wall, which can reduce the Q-factor and efficiency of the cavity. In order to increase the Q-factor, it is important to lower the surface resistance by reducing the amount of magnetic flux trapped in the cavity wall to sub 10mG range during the Tc transition. In this paper, we present a 3-axis automatic active magnetic field compensation system that is capable of reducing the earth magnetic field and any local disturbance field. Design techniques are described to enhance the system stability while utilizing the flexibility of embedded electronics. This paper describes the system implementation and concludes with initial results of tests. Experimental results demonstrate that the proposed magnetic field compensation system can reduce the earth magnetic field to around 2.5 mG even without shielding. PB - JACoW Publishing CP - Geneva, Switzerland SP - 101 EP - 103 KW - cavity KW - SRF KW - controls KW - electron KW - electronics DA - 2018/11 PY - 2018 SN - 978-3-95450-201-1 DO - 10.18429/JACoW-IBIC2018-MOPB13 UR - http://jacow.org/ibic2018/papers/mopb13.pdf ER -